Weather forecasters say the Olympic torch relay on Wednesday could coincide with the hottest day of the year, with temperatures set to reach 31°C.

The Met Office says temperatures are expected to rise day by day until mid-week, with Wednesday predicted to be the warmest day of the year, beating the 29.3°C recorded in the Scottish Highlands in May.

The Olympic Torch arrives in Harrow on Wednesday morning, before winding its way through Brent, Barnet, Enfield and Haringey to reach a celebration at Alexandra Palace in the evening.

Met Office forecaster Nick Grahame said: “British summer weather is, by its very nature, quite variable and this spell of very warm weather is only expected to last a couple of days.

“Temperatures will gradually fall away again through Thursday and Friday and although there is still a lot to play for the forecast for the end of the week, there is the potential for showers to develop in the south on Friday.”